Alert archive / Alabama / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 147, NWS Birmingham, AL

April 11, 20118 counties in Alabama

NWS Birmingham, AL issued this severe thunderstorm warning at Apr 11, 2011, 9:26 PM CDT for 8 counties in Alabama. It was in force for 49 min. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Apr 11, 2011, 9:26 PM CDT (02:26 UTC)
Expired: Apr 11, 2011, 10:15 PM CDT
In force: 49 min
Issued by: NWS Birmingham, AL
Area: Storm-based polygon

Counties Chambers County, AL, Clay County, AL, Elmore County, AL, Lee County, AL, Macon County, AL, Montgomery County, AL, Randolph County, AL, Tallapoosa County, AL

What was reported inside it

Time	Report	Where	Remark
Apr 11, 9:33 PM CDT	TSTM WND DMG	2 Nw Dadeville, AL	TREES DOWN IN AREA.
Apr 11, 10:03 PM CDT	TSTM WND DMG	3 Se Tallapoosa River A, AL	TREES DOWN IN AREA.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

Did it verify

Verified. The Iowa Environmental Mesonet's Cow matched 2 storm reports to this severe thunderstorm warning; the first came 7 minutes after it went out.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Apr 11, 7:08 PM CDT	Tornado Watch	SPC	7 hr

The nearest sounding before it

Birmingham, AL (KBMX), launched 00:00Z, 2.4 hours before the alert went out and 104 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 557 J/kg
Mixed-layer CIN: -23 J/kg
Mixed-layer LCL: 1487 m above ground
0-6 km bulk shear: 69 kt
0-1 km storm-relative helicity: 271 m²/s²
0-3 km storm-relative helicity: 323 m²/s²
Significant tornado parameter: 0.6
Supercell composite: 9.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

762 
WUUS54 KBMX 120226
SVRBMX
ALC017-027-051-081-087-101-111-123-120315-
/O.NEW.KBMX.SV.W.0147.110412T0226Z-110412T0315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE BIRMINGHAM AL
926 PM CDT MON APR 11 2011

THE NATIONAL WEATHER SERVICE IN BIRMINGHAM HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CHAMBERS COUNTY IN EAST CENTRAL ALABAMA...
  SOUTHEASTERN CLAY COUNTY IN EAST CENTRAL ALABAMA...
  EASTERN ELMORE COUNTY IN EAST CENTRAL ALABAMA...
  NORTHWESTERN LEE COUNTY IN EAST CENTRAL ALABAMA...
  NORTHWESTERN MACON COUNTY IN SOUTHEAST ALABAMA...
  NORTH CENTRAL MONTGOMERY COUNTY IN SOUTH CENTRAL ALABAMA...
  RANDOLPH COUNTY IN EAST CENTRAL ALABAMA...
  TALLAPOOSA COUNTY IN EAST CENTRAL ALABAMA...

* UNTIL 1015 PM CDT

* AT 921 PM CDT...THE NATIONAL WEATHER SERVICE INDICATED A LINE OF
  SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS
  OF 60 MPH.  THESE STORMS WERE LOCATED ALONG A LINE EXTENDING FROM
  WEDOWEE TO BLUE RIDGE...AND MOVING EAST AT 50 MPH.

* LOCATIONS IMPACTED INCLUDE...
  DADEVILLE...ROANOKE...TALLASSEE...CAMP HILL...MILSTEAD...STROUD...
  LAFAYETTE AND NOTASULGA.

THIS INCLUDES...
INTERSTATE 85 EXIT NUMBERS 26 THROUGH 42...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FOR YOUR PROTECTION...MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF
YOUR HOME OR BUSINESS.

THESE STORMS HAVE A HISTORY OF PRODUCING WIND DAMAGE ACROSS CENTRAL 
ALABAMA. THIS IS AN EXTREMELY DANGEROUS SITUATION. SEEK SHELTER NOW 
INSIDE A STURDY STRUCTURE AND STAY AWAY FROM WINDOWS.

&&

A TORNADO WATCH REMAINS IN EFFECT UNTIL 1100 PM CDT MONDAY EVENING
FOR SOUTH CENTRAL ALABAMA. A TORNADO WATCH ALSO REMAINS IN EFFECT
UNTIL 200 AM CDT TUESDAY MORNING FOR EASTERN ALABAMA.

TO REPORT SEVERE WEATHER...
CALL 1-800-856-0758.

LAT...LON 3241 8562 3242 8636 3276 8608 3276 8601
      3284 8601 3347 8545 3347 8529 3300 8520
TIME...MOT...LOC 0226Z 267DEG 43KT 3329 8544 3246 8616

$$

56

1 follow-up statement

640 
WWUS54 KBMX 120310
SVSBMX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
1010 PM CDT MON APR 11 2011

ALC027-101-111-120321-
/O.CAN.KBMX.SV.W.0147.000000T0000Z-110412T0315Z/
MONTGOMERY AL-CLAY AL-RANDOLPH AL-
1010 PM CDT MON APR 11 2011

...THE SEVERE THUNDERSTORM WARNING FOR RANDOLPH...SOUTHEASTERN CLAY
AND NORTH CENTRAL MONTGOMERY COUNTIES IS CANCELLED...

THE LINE OF STORMS WHICH PROMPTED THE WARNING HAVE MOVED OUT OF THE 
WARNED AREA.

TO REPORT SEVERE WEATHER...CALL 1-800-856-0758.

LAT...LON 3242 8598 3266 8587 3273 8581 3283 8578
      3282 8560 3283 8532 3241 8562
TIME...MOT...LOC 0311Z 267DEG 43KT 3277 8545 3247 8566

$$

ALC017-051-081-087-123-120315-
/O.CON.KBMX.SV.W.0147.000000T0000Z-110412T0315Z/
MACON AL-LEE AL-ELMORE AL-TALLAPOOSA AL-CHAMBERS AL-
1010 PM CDT MON APR 11 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR SOUTHWESTERN
CHAMBERS...SOUTHEASTERN TALLAPOOSA...SOUTHEASTERN ELMORE...
NORTHWESTERN LEE AND NORTHWESTERN MACON COUNTIES UNTIL 1015 PM CDT...

AT 1008 PM CDT...A ***YOU FORGOT TO SELECT A DEFAULT OPTION*** 
DAMAGING WINDS IN EXCESS OF 60 MPH.  THESE STORMS WERE LOCATED ALONG
A LINE EXTENDING FROM STURKIE TO TUSKEGEE...MOVING EAST AT 50 MPH.

LOCATIONS IMPACTED INCLUDE...
  OAK BOWERY...TUSKEGEE NATIONAL FOREST...AUBURN UNIVERSITY AND I 85
  REST AREA.

THIS INCLUDES...
INTERSTATE 85 EXIT NUMBERS 26 THROUGH 42...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO WATCH REMAINS IN EFFECT FOR THE WARNED AREA. TORNADOES CAN
DEVELOP QUICKLY FROM SEVERE THUNDERSTORMS. ALTHOUGH NOT IMMEDIATELY
LIKELY...IF A TORNADO IS SPOTTED ACT QUICKLY AND MOVE TO A PLACE OF
SAFETY INSIDE A STURDY STRUCTURE...SUCH AS A BASEMENT OR SMALL
INTERIOR ROOM.

&&

TO REPORT SEVERE WEATHER...CALL 1-800-856-0758.

LAT...LON 3242 8598 3266 8587 3273 8581 3283 8578
      3282 8560 3283 8532 3241 8562
TIME...MOT...LOC 0311Z 267DEG 43KT 3277 8545 3247 8566

$$

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Birmingham, AL wrote its last area forecast discussion before this severe thunderstorm warning went out at Apr 11, 6:47 PM CDT, 2 hours 39 minutes earlier.

Area forecast discussion, Apr 11, 6:47 PM CDT, 2 hours 39 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
647 PM CDT MON APR 11 2011

.UPDATE...AVIATION DISCUSSION.

&&

.DISCUSSION...

ENVIRONMENT WILL SLOWLY DESTABILIZE ACROSS THE AREA THRU THE
REMAINDER OF THE AFTN AS THE CAPE THAT HAS BEEN IN PLACE ALL DAY
FINALLY ERODES. SQUALL LINE HAS HAD A HARD TIME PROGRESSING EWD THUS
FAR BUT IS EXPECTED TO PICK UP FORWARD SPEED AS THE DAY PROGRESSES
AND THE SFC RIDGE BREAKS DOWN. PREVIOUS TIMING FOR THE WRN HALF OF
THE CWA HAS BEEN PUSHED BACK TO ACCOUNT FOR THIS SLOWER TREND.
HOWEVER TIMING IN THE EAST IS STILL REPRESENTATIVE. STRONG SWRLY
WINDS AND DRY AIR ALOFT WILL KEEP THE DAMAGING WIND THREAT HIGH.
SOME LARGE HAIL IS ALSO POSSIBLE BUT TO A SMALLER DEGREE THAN THE
WINDS. ISOLATED TORNADOES AND FLOODING WILL PRESENT THE LOWEST
THREAT WITH THIS SYSTEM. THE LINE SHOULD MOVE QUICKLY ENOUGH THRU
THE AREA TO PREVENT ANY WIDESPREAD FLOODING CONCERNS...BUT TRAINING
CELLS COULD LEAD TO SOME BRIEF LOCALIZED FLASH FLOODING ISSUES. EVEN
THOUGH THE THREAT FOR TORNADOES IS RATHER LOW...THERE IS THE
POSSIBILITY OF A BRIEF SPIN-UP WITHIN THE LINE...ESPECIALLY W OF
I-65.

MORE PLEASANT WEATHER IS IN STORE ON TUE AS A SLIGHTLY DRIER AND
COOLER AIR MASS FILTERS INTO THE REGION. TEMPS WILL NOT DROP
SIGNIFICANTLY BUT THEY SHOULD AT LEAST FALL BACK TO NORMAL FOR THIS
TIME OF YEAR...WITH HIGHS IN THE UPPER 60S NORTH TO MID 70S SOUTH.
SFC HIGH PRESSURE WILL STICK AROUND THRU WED AND THEN BEGIN TO PUSH
OFF TO THE E AS THE NEXT STORM SYSTEM TAKES SHAPE TO OUR W. THE SFC
LOW ASSOCIATED WITH THIS SECOND SYSTEM WILL TRACK EWD DRAGGING
ANOTHER COLD FRONT THRU THE AREA LATE IN THE WEEK. MODEL DIFFERENCES
ARE STILL TOO GREAT FOR DETERMINING ANY DETAILS...BUT IT DOES APPEAR
THAT THE FRONT AND ASSOCIATED SHOWERS/STORMS WILL MOST LIKELY MOVE
THRU LATE FRI. THIS SCENARIO WOULD PAVE THE WAY FOR A FAIRLY NICE
AND QUIET WEEKEND ACROSS CENTRAL ALABAMA. THIS IS UNLESS MODELS
BEGIN TO SLOW THE SYSTEM DOWN...WHICH THEY TEND TO DO.

19

&&

.AVIATION...
00Z TAF DISCUSSION.

LINE OF SHOWERS AND THUNDERSTORMS CONTINUES TO PLOW ACROSS CENTRAL
ALABAMA THIS EVENING. SOME OF THESE STORMS COULD PRODUCE DAMAGING
WINDS. THIS LINE IS EXPECTED TO AFFECT ALL TAF SITES THIS EVENING.
BY 06Z...COLD FRONT WILL BE MOVING THROUGH AND WINDS WILL SHIFT MORE
TO THE NORTHWEST.

ONCE THE FRONT MOVES THROUGH...EXPECT A BRIEF PERIOD OF MVFR
CEILINGS...BUT FELT CONFIDENT ENOUGH TO CLEAR SKIES FROM WEST TO
EAST AFTER 06Z ACROSS ALL SITES.

WINDS WILL REMAIN GUSTY TOMORROW BUT NOT NEARLY AS STRONG AS THEY
WERE TODAY.

NOTICE...KEET TAF WILL HAVE (AMD LTD TO VIS WIND AND WX) AMENDED TO
THE END OF THE FORECAST UNTIL FURTHER NOTICE. THE CEILOMETER DATA
WILL BE GOING THROUGH NUMEROUS TESTS AND MONITORED FOR ACCURACY.

10/ARM

&&

.BMX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR ALL OF CENTRAL ALABAMA.

&&

19/10

Hazardous weather outlook, Apr 11, 9:25 PM CDT, 1 minute before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BIRMINGHAM AL
925 PM CDT MON APR 11 2011

ALZ011>015-017>050-130000-
AUTAUGA-BARBOUR-BIBB-BLOUNT-BULLOCK-CALHOUN-CHAMBERS-CHEROKEE-
CHILTON-CLAY-CLEBURNE-COOSA-DALLAS-ELMORE-ETOWAH-FAYETTE-GREENE-HALE-
JEFFERSON-LAMAR-LEE-LOWNDES-MACON-MARENGO-MARION-MONTGOMERY-PERRY-
PICKENS-PIKE-RANDOLPH-RUSSELL-SHELBY-ST CLAIR-SUMTER-TALLADEGA-
TALLAPOOSA-TUSCALOOSA-WALKER-WINSTON-
925 PM CDT MON APR 11 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE COUNTIES SERVED BY THE
NATIONAL WEATHER SERVICE OFFICE IN BIRMINGHAM.

.DAY ONE...TONIGHT.

SEVERE THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE THE SOUTHEAST HALF
OF CENTRAL ALABAMA THROUGH THE EVENING. MAIN THREAT AREAS ARE ALONG
AND EAST OF A ELLISVILLE TO WHITE HALL LINE. THE HAZARDOUS THREATS
WITH THESE STORMS INCLUDE DAMAGING WINDS AND LARGE HAIL. ISOLATED
TORNADOES ARE ALSO POSSIBLE EMBEDDED WITHIN THE LINE OF
THUNDERSTORMS. THESE STORMS WILL FORM ALONG AND AHEAD OF A COLD
FRONT THAT WILL MOVE WEST TO EAST THROUGH TONIGHT.

WINDY CONDITIONS ARE EXPECTED TONIGHT. SOUTH TO SOUTHWEST WINDS OF
15 TO 20 MPH WITH GUSTS OF 30 TO 35 MPH ARE ANTICIPATED AHEAD OF THE
COLD FRONT. THESE WINDS ARE EXPECTED OUTSIDE THE THUNDERSTORM AREAS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

WINDY CONDITIONS ARE POSSIBLE BEHIND A STRONG COLD FRONT ON SATURDAY.

.SPOTTER INFORMATION STATEMENT...

ACTIVATION OF STORM SPOTTERS AND EMERGENCY MANAGEMENT PERSONNEL WILL
CONTINUE TO BE NECESSARY TONIGHT DUE TO THE SEVERE WEATHER THREAT.

08/MNK

In the hours before

Local storm report, Apr 11, 9:07 PM CDT, 19 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
907 PM CDT MON APR 11 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0631 PM     TSTM WND DMG     6 W NORTHPORT           33.25N 87.69W
04/11/2011                   TUSCALOOSA         AL   EMERGENCY MNGR

            TREES DOWN ALONG SIPSEY VALLEY ROAD AND COUNTY ROAD 140.

&&

JT

Local storm report, Apr 11, 9:10 PM CDT, 16 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
910 PM CDT MON APR 11 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0631 PM     TSTM WND DMG     4 NNE HOLT              33.30N 87.48W
04/11/2011                   TUSCALOOSA         AL   EMERGENCY MNGR

            NUMEROUS TREES DOWN AROUND LAKE NICOL.

&&

JT

Local storm report, Apr 11, 9:12 PM CDT, 14 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
912 PM CDT MON APR 11 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0545 PM     TSTM WND DMG     FAYETTE                 33.69N 87.83W
04/11/2011                   FAYETTE            AL   EMERGENCY MNGR

            METAL ROOF PARTIALLY BLOWN OFF FACTORY IN FAYETTE. ROOF
            DAMAGE TO SMALL BUILDING AND HOME 1 MILE EAST OF FAYETTE
            ON CR 26N. NUMEROUS TRESS ACROSS COUNTY.

&&

JT

Local storm report, Apr 11, 9:17 PM CDT, 9 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
917 PM CDT MON APR 11 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0821 PM     TSTM WND DMG     2 SSE SELMA             32.39N 87.01W
04/11/2011                   DALLAS             AL   EMERGENCY MNGR

            TREES DOWN ON OLD MONTGOMERY ROAD.

&&

JT

Local storm report, Apr 11, 9:21 PM CDT, 5 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
921 PM CDT MON APR 11 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0714 PM     TSTM WND DMG     3 NNW FAIRFIELD         33.52N 86.94W
04/11/2011                   JEFFERSON          AL   AMATEUR RADIO

            TREE DOWN BLOCKING HWY 269 NEAR MINOR HIGH SCHOOL

&&

JT

Local storm report, Apr 11, 9:24 PM CDT, 2 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
924 PM CDT MON APR 11 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0658 PM     TSTM WND DMG     4 WSW BLOUNT SPRINGS    33.91N 86.87W
04/11/2011                   BLOUNT             AL   EMERGENCY MNGR

            TREES DOWN NEAR MILE MARKER 288 ON INTERSTATE 65.

&&

JT

The office that day

Everything else NWS Birmingham, AL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 11, 7:19 PM CDT	Tornado Warning	BMX	Jefferson, Shelby	21 min
Apr 11, 7:28 PM CDT	Severe Thunderstorm Warning	BMX	Blount, Calhoun, Etowah, Jefferson, St. Clair, Talladega	62 min
Apr 11, 7:30 PM CDT	Severe Thunderstorm Warning	BMX	Dallas, Hale, Marengo, Perry	60 min
Apr 11, 7:34 PM CDT	Tornado Warning	BMX	Marengo	26 min
Apr 11, 7:34 PM CDT	Tornado Warning	BMX	Jefferson, St. Clair, Shelby	19 min
Apr 11, 7:41 PM CDT	Severe Thunderstorm Warning	BMX	Autauga, Bibb, Chilton, Clay, Coosa, Dallas and 4 more	64 min
Apr 11, 8:03 PM CDT	Severe Thunderstorm Warning	BMX	Calhoun, Cherokee, Clay, Cleburne, Etowah, Randolph and 2 more	57 min
Apr 11, 8:20 PM CDT	Severe Thunderstorm Warning	BMX	Autauga, Dallas, Lowndes	40 min
Apr 11, 8:39 PM CDT	Severe Thunderstorm Warning	BMX	Autauga, Chambers, Clay, Coosa, Elmore, Montgomery and 3 more	66 min
Apr 11, 8:52 PM CDT	Severe Thunderstorm Warning	BMX	Calhoun, Cherokee, Clay, Cleburne, Randolph	38 min
Apr 11, 8:53 PM CDT	Severe Thunderstorm Warning	BMX	Autauga, Dallas, Lowndes, Montgomery, Pike	67 min
Apr 11, 8:57 PM CDT	Tornado Warning	BMX	Cleburne	33 min
Apr 11, 10:01 PM CDT	Severe Thunderstorm Warning	BMX	Bullock, Lee, Macon, Montgomery, Russell	44 min

Nearby

Severe Thunderstorm Warnings in Alabama, 2011 Every severe thunderstorm warning in 2011

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive.